Zénobe Théophile Gramme (Jehay-Bodegnée, 4 April 1826 – Bois-Colombes, 20 January 1901) was a Belgian electrical engineer.
He invented the Gramme machine, a type of direct current dynamo capable of generating smoother (less AC) and much higher voltages than the dynamos known to that point. Gramme was poorly educated and semi-literate throughout his life. His talent was in handicraft and when he left school became a joiner. After moving to Paris he took a job as a model maker at a company that manufactured electrical equipment and there became interested in technology. Having built an improved dynamo Gramme, in association with Hippolyte Fontaine, he opened a factory to develop the device. The business, called Société des Machines Magnéto-Électriques Gramme, manufactured the Gramme dynamo, Gramme ring, Gramme armature and other devices. In 1873 a Gramme dynamo was exhibited at the Vienna exhibition.
In 1873 he and Hippolyte Fontaine accidentally discovered that the device was reversible and would spin when connected to any DC power supply. The Gramme machine was the first usefully powerful electrical motor that was successful industrially. Before Gramme’s inventions, electric motors attained only low power and were mainly used as toys or laboratory curiosities. In 1875, Nikola Tesla observed a Gramme machine at the Graz University of Technology. He conceived the idea of using it for alternating current but was unable to develop the idea at this time.
He was made an officer of the National Order of the Legion of Honour in 1877. In 1888 he was awarded the last of the valuable Volta Prizes by the French government.
The extra thick coin measures 70 by 45 MM in size .
The front and back are a 3D cast zinc alloy with all 3 sides polished and with antique bronze plating.
The coin comes in a black velvet pouch!
The antique bronze plating is an extra extra limited edition – 20.
The tracking codes have the BE prefix.
This item has a unique icon, and is trackable at geocaching.com.